diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index aed47db79b..8d722a9185 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
@@ -3868,7 +3868,7 @@ SELECT TIMESTAMP 'now';
#
- Number of points in polygon
+ Number of points in path or polygon
# '((1,0),(0,1),(-1,0))'
@@ -4025,6 +4025,18 @@ SELECT TIMESTAMP 'now';
length of item
length(path '((-1,0),(1,0))')
+
+ npoints(path)
+ integer
+ number of points
+ npoints(path '[(0,0),(1,1),(2,0)]')
+
+
+ npoints(polygon)
+ integer
+ number of points
+ npoints(polygon '((1,1),(0,0))')
+
pclose(path)
path
@@ -4040,12 +4052,6 @@ SELECT TIMESTAMP 'now';
point(lseg '((-1,0),(1,0))',lseg '((-2,-2),(2,2))')
]]>
-
- npoint(path)
- integer
- number of points
- npoints(path '[(0,0),(1,1),(2,0)]')
-
popen(path)
path
@@ -4150,7 +4156,7 @@ SELECT TIMESTAMP 'now';
polygon(box)
polygon
- 12 point polygon
+ 4-point polygon
polygon(box '((0,0),(1,1))')
@@ -4175,6 +4181,16 @@ SELECT TIMESTAMP 'now';
+
+ It is possible to access the two component numbers of a point
+ as though it were an array with subscripts 0,1. For example, if
+ t.p is a point column then
+ SELECT p[0] FROM t retrieves the X coordinate;
+ UPDATE t SET p[1] = ... changes the Y coordinate.
+ In the same way, a box or an lseg may be treated
+ as an array of two points.
+
+